A Semi-quantitative analysis of immunohistochemical expression of p63, Ki-67, Cyclin-D1, and p16 in common oral potentially malignant disorders and oral squamous cell carcinoma

Abstract

Background: Immunohistochemical (IHC) expressions of p63, Ki-67, cyclin-D1, and p16 have been evaluated to assess the malignant potential of oral potentially malignant disorders (OPMDs); most of these studies are subjective and lack a definite quantitative approach. Further, H score of IHC expression has produced promising results and this has not been explored in any marker to predict malignant transformation in OPMDs. Aim: To evaluate the IHC expressions of p63, Ki-67, cyclin-D1, and p16INK4a in predicting the malignant transformation of the most common OPMDs. Materials and Methods: The IHC expressions of p63, Ki-67, cyclin-D1, and p16INK4a on paraffin-embedded sections of 10 cases each in normal oral mucosa, mild, moderate, and severe oral epithelial dysplasia, oral submucous fibrosis (OSMF), and oral squamous cell carcinoma (OSSC) were evaluated using mean H score for every group. Mean H score was compared within and between the groups using analysis of variance. Pairwise comparison was made using Tukey's multiple post hoc procedure and strength of association was assessed using Karl's Pearson's correlation. Results: Mean H scores of p63, Ki-67, and cyclin-D1 increased significantly (P = 0.0001) with increasing grades of dysplasia to OSCC, whereas mean H score of p16 significantly (0.041) decreased with increasing grades of dysplasia to malignancy. OSMF indicated a variation in its expression pattern. Only mean H scores of Ki-67 (0.0239) and cyclin-D1 (0.0044) significantly differentiated severe dysplasia from OSCC. Conclusion: Combination of mean H score of Ki-67 and mean H score of cyclin-D1 could be effectively used to identify transformation potential of OPMDs.

Keywords

• Cyclin-D1
• H score
• Ki-67
• p16INK4a
• p63